Keyed dead front electrical connector and cap



Feb. 1, 1966 J. A. KENNEDY ET AL 3,233,203

KEYED DEAD FRONT ELECTRICAL CONNECTOR AND CAP Filed NOV. 17, 1964 12 INVENTORS'.

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United States Patent 3,233,203 KEYED DEAD FRONT ELECTRICAL CONNECTOR AND CAP James A. Kennedy, Short Hills, N.J., and William A. Sunter, Fairfield, Conn., assignors to Harvey Hubbel, Incorporated, Bridgeport, Conn, a corporation of Connecticut Filed Nov. 17, 1964, Ser. No. 411,831 7 Claims. (Cl. 339-42) This invention relates to interlocking dead front electrical connectors and, more particularly, to such a connector having keying means.

In United States Patent 2,102,625 which was issued December 21, 1937 to Harvey Hubbell, In, there is disclosed an interlocking receptacle, connector, and cap of the dead front type. In a connector assembly of this type, the receptacle or connector portion defines an opening which is normally closed by an insulating plunger. The female electrical contacts are positioned within the receptacle or connector. The cap portion of a connector assembly of this type includes a central post formed of an insulating material having the male contacts positioned thereon. Upon advancing the cap into the receptacle, the post depresses the plunger and electrical contact is made and, upon full insertion, the cap is then rotated to lock the connector assembly elements together.

In United States Patent 3,120,985 which issued to Harvey Hubbel on February 11, 1964, there is disclosed and claimed an electrical connector having selective key means for different voltages. The connector disclosed in that patent includes a body having spaced slots disposed concentrically around a central opening. Each of the slots communicates with a recess containing the female electrical contacts. of arcuate blade members which are positioned for insertion into the various slots. Extending outwardly from the cap and centrally of the blades there is a rotatable key member which has a cross-sectional configuration matching that of the central opening in the connector body. In joining the cap and the connector, the cap blades enterthe corresponding slots of the connector body and the key enters the central opening. Upon full insertion, the cap may be rotated relative to the connector body so as to cause the two to interlock. One advantage of a construction of this type is that the cross-sectional configuration of the opening and the key member may be varied to suit different voltages and different load con- Accordingly it would be impossible to insert a cap into a connector having a different rating as the key would not be insertable into the opening.

It would be highly desirable to apply the principle of selective keying to connectors of th dead front type. However, until the present invention this has not been readily achievable. One reason for this is that the basic function of keying is to prevent electrical connection between caps and connectors of different ratings. Since this requirement is of an exclusionary nature, it is not sufficient merely to provide that two similarly rated ele- It is additionally important to insure that a cap and a connector of differing ratings will not interconnect. The difiiculty raised by this requirement of exclusion may be best appreciated by considering a connector assembly keying arrangement which would not operate. This would consist of a connector having a keying opening in its plunger. Although this arrangement would prevent th interlocking of improperly rated keyed caps, it will be apparent that either a cap having a short key member at its forward end or an unkeyed cap could be inserted into an improperly rated connector, at least to the point of engagement between the cap and connector electrical contacts.

The cap portion includes a plurality ,Wall, of the connector.

tive to the insert.

3,233,203 Patented Feb. 1, 1966 Accordingly, it is the primary object of the present invention to provide an improved interlocking dead front electrical connector having keying means. Other objects are to provide such a connector which is highly selective in allowing interconnection only between similarly rated elements; wherein the keying means are readily interchangeable; and which is inexpensive, reliable, and essentially maintenance free.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims, and the figures of the attached drawing wherein:

FIG. 1 is an illustration of a connector and cap aligned to be interconnected with one another, portions thereof being broken away to illustrate the internal construction;

FIG. 2 is a right end view of the connector shown in FIG. 1;

FIG. 3 is a left end view of the cap shown in FIG. 1;

FIG. 4 is a cross section taken along the line 44 of FIG. 2 but showing the cap inserted in the connector, and

FIG. 5 is a cross section taken along the line 5-5 of FIG. 4.

In accordance with the present invention, there is provided a connector of the dead front type having a keying pin positioned therein and extending through the usual plunger. The cap includes an insert defining an opening for receiving the end of the keying pin.

With particular reference to the drawings, there is illustrated a connector R of the dead front type and a cap C designed to mate therewith. The connector R includes a cylindrical body 10 of insulating material defining therein the usual recesses 12 for containing the electrical contacts 14. The body also defines a central chamber 16 communicating with the recesses 12 and extending from the front axially toward the rear. The connector R includes clamp-type terminals 18 for wiring the individual conductors of an electrical cord 20. The body 10 is enclosed within a metallic shell 22. A plunger 24 of insulating material is positioned to slide within the central chamber 16 longitudinally of the axis of the connector R. At its outermost position, the plunger 24 substantially closes the end of the connector so as to provide the desired dead front feature. A coil spring 26 is mounted in the connector body to bias the plunger outwardly and serves to keep the plunger in the closed position when the connector is not connected to a cap. A metal insert 28, knurled on its outer surface, is force fitted into a corresponding recess 30 provided in a diametral inner surface of the back of the central chamber 16. The insert 28 is generally cylindrical and supports a keying pin 32 therein. Keying pin 32 extends along the axis of the central bore 16 and through a circular opening 34 in plunger 24 to a point just beyond the diametral front The major portion of the length of keying pin 32 is shaped to a selectively predetermined desired cross section. In the illustrated embodiment, this cross section is triangular. The inner end 33 of the keying pin 32 is cylindrical and fits within the central opening of the metal insert 28. A washer 36 abuts against the triangular shaped portion and positions the pin 32 rela- The end of the pin 32 is then riveted over the end of the insert, as at 38, so as to secure it in position. The pin 32 is not riveted tightly enough to the insert 28 to prevent its rotation, but is secured tightly enough to maintain the axial alignment of the triangular shape-d portion of the pin with the central chamber 16.

The construction of cap C is similar to the construction of the cap illustrated in Patent No. 2,102,625 referred to above. It includes a cylindrical body 40 of insulating material enclosed within a metallic shell 42. A central post 44 extends axially outwardly of the body 40 and carries on its outer peripheral surface electrical contacts 46 arranged to mate with the contacts 14 within the connector body 10. The post 44 of this invention is provided with a central opening within which is fixedly secured an insert 48 of a suitable plastic material, such as nylon. The insert 48 defines a central opening 50 which is shaped to receive the keying pin 32 of a connector.

In operation, as the cap C and the connector R are brought into juxtaposition, the keying pin 32 enters the opening St} in the end of post insert 48. Continued advancement of the cap relative to the connector re sults in the post engaging and forcing the plunger 24 inwardly to the position illustrated in FIG. 4. The electrical contacts 46 on the cap engage the electrical contacts 14 within the connector. The cap C is then rotated in the usual fashion to effect the interlocking connection between it and the connector. The keying pin 32 rotates with the insert 48 as the insert turns to permit such interlocking. Removal is effected by rotatingthe cap in the opposite direction and withdrawing it from the connector.

It will be apparent that by proper selection of crosssectional configurations for the keying pin '32 and the insert 48, connectors and caps may be jointly rated so that incorrectly rated components cannot be interconnected. Furthermore, keying may be readily changed by removing the inserts 28 and 48 and the keying pin 32 and substituting a differently configured keying pin and insert. It will be obvious to those skilled in the art that a number of variations and modifications may be made in this invention without departing from its spirit and scope. Accordingly, it is to be understood that the foregoing description is illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What we claim as new and desire to secure by Letters Patent of the United States is: v

1. An electrical connector assembly which'comprises: a connector having a body of insulating material; said connector body including a front surface and defining a chamber therein communicating with said front surface; first electrical contact means positioned within said chamber; closure means slidably retained in said chamber for movement bet-ween a first position adjacent said front surface and a second position within said chamber; said closure means defining an opening therethrough; means within said chamber positioned to bias said closure means toward and into said first position; keying pin means rotatably mounted in said connector body and extending centrally through said chamber and the opening in said closure means to a point outwardly of said closure means, the free end of said keying pin means having a non-circular cross-section; a cap having a body of insulating material; said cap including a central post arranged to selectively enter said chamber in said connector by engaging and moving said closure means against its bias; said post member defining an opening therethrough having a I non-circular cross sectional shape conforming to that of the pin means to closely but slidably engage said keying pin means; and second electrical contact means positioned on said post member to engage said first electrical contact means; said cap and connector having interlocking means operative on their relative rotation.

2. The connector assembly of claim 1 wherein there is included means rotatably mounting said keying pin means.

3. The connector assembly of claim 2 wherein said mounting means comprises an insert in Stllti connector,

and said keying pin means includes a cylindrical end rotatably retained in said insert.

4. The connector assembly of claim 1 wherein said post member includes an insert defining the opening therein.

5. An electrical connector which comprises: a body of insulating material including a front surface and defining a chamber therein communicating with said front surface; a plurality of electrical contact means positioned within said chamber; means for electrically connecting said contact means to electrical conductor means; closure means slidably retained in said chamber for movement between a first position adjacent said front surface and a second position within said chamber; said closure means defining an opening therethrough; means within said chamber positioned to bias said closure means into said first position; and keying pin means rotatably mounted in said connector and extending through said chamber and the opening in said closure means to a point outwardly of said closure means; said keying pin means having a noncircular cross section along at least a portion of its length.

6. An electrical connector which comprises: a body of insulating material including a front surface, a chamber communicating with said front surface, and a tubular insert in said chamber; a plurality of electrical contact means positioned within said chamber; means for electrically connecting said contact means to electricalconductor means; closure means slidably retained in said chamber for movement between a first positionadja-cent said front surface and a second position withinsaid chamber; said closure means defining anopening therethrough; means within said chamber positioned to bias said closure means into said first position; and keying pin means mounted in said connector including a cylindrical end rotatably retained in said insert and extending through said chamber and the opening in said closure means to a point outwardly of said closure means, said keying pin means having a non-circular cross-section along at least aportion of its length. p

7. An electrical connector which comprises: a body of insulating material-including a front surface, a chamber communicating with said front surface, and a tubular insert in said chamber; a plurality of electricalcontact means positioned within said chamber; means for electrically connecting said contact means to electrical conductor means; closure means slidably retained in said chamber for movement between a first position adjacent said front surface and a second position within said chamber; said closure means defining an opening therethrough; keying pin means mounted in said connector including a cylindrical end rotatablyretained in said insert and extendingthrough said chamber and the opening in said closure means to a point outwardly of said closure means, said keying pin means having a non-cir cular cross-section along at least a portion of its length; and a coil spring within said chamber substantially encircling said keying pin means and positioned to bias said closure'means into said first position.

References Cited by the Examiner Hubbell 3 393 1 JOSEPH D. SEERS, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,233,203 February 1, 1966 James A. Kennedy et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent-should read as corrected below.

In the grant, lines 3 and I4, and in the heading to the printed specification, lines 5 and 6, for "Harvey Hubbel,

Incorporated", each occurrence, read Harvey Hubbell, Incorporated column 1, line 29, for "Hubbel" read Hubbell Signed and sealed this 3rd day of January 1967.

( Afloat: MESTW, EDWARD I. BRENNER testing Officer Commissioner of Patcms 

5. AN ELECTRICAL CONNECTOR WHICH COMPRISES: A BODY OF INSULATING MATERIAL INCLUDING A FRONT SURFACE AND DEFINING A CHAMBER THEREIN COMMUNICATING WITH SAID FRONT SURFACE; A PLURALITY OF ELECTRICAL CONTACT MEANS POSITIONED WITHIN SAID CHAMBER; MEANS FOR ELECTRICALLY CONNECTING SAID CONTACT MEANS TO ELECTRICAL CONDUCTOR MEANS; CLOSURE MEANS SLIDABLY RETAINED IN SAID CHAMBER FOR MOVEMENT BETWEEN A FIRST POSITION ADJACENT SAID FRONT SURFACE AND A SECOND POSITION WITHIN SAID CHAMBER; SAID CLOSURE MEANS DEFINING AN OPENING THERETHROUGH; MEANS WITHIN SAID CHAMBER POSITIONED TO BIAS SAID CLOSURE MEANS INTO SAID FIRST POSITION; AND KEYING PINS MEANS ROTATABLY MOUNTED IN SAID CONNECTOR AND EXTENDING THROUGH SAID CHAMBER AND THE OPENING IN SAID CLOSURE MEANS TO A POINT OUTWARDLY OF SAID CLOSURE MEANS; SAID KEYING PIN MEANS HAVING A NONCIRCULAR CROSS SECTION ALONG AT LEAST A PORTION OF ITS LENGTH. 